Our medical policies are designed for informational purposes only and are not an authorization, or an explanation of benefits, or a contract. Receipt of benefits is subject to satisfaction of all terms and conditions of the coverage. Medical technology is constantly changing, and we reserve the right to review and update our policies periodically.

Description

Radiation techniques

Conventional external-beam radiation therapy

Over the past several decades, methods to plan and deliver radiation therapy have evolved in ways that permit more precise targeting of tumors with complex geometries. Most early trials used 2-dimensional treatment planning, based on flat images and radiation beams with cross-sections of uniform intensity that were sequentially aimed at the tumor along 2 or 3 intersecting axes. Collectively, these methods are termed conventional external-beam radiation therapy.

Three-dimensional conformal radiation

Treatment planning evolved by using 3-dimensional images, usually from computed tomography (CT) scans, to delineate the boundaries of the tumor and discriminate tumor tissue from adjacent normal tissue and nearby organs at risk for radiation damage. Computer algorithms were developed to estimate cumulative radiation dose delivered to each volume of interest by summing the contribution from each shaped beam. Methods also were developed to position the patient and the radiation portal reproducibly for each fraction and immobilize the patient, thus maintaining consistent beam axes across treatment sessions. Collectively, these methods are termed 3-dimensional conformal radiation therapy (3D-CRT).

Intensity-modulated radiation therapy

IMRT, which uses computer software, CT images, and magnetic resonance imaging, offers better conformality than 3D-CRT as it is able to modulate the intensity of the overlapping radiation beams projected on the target and to use multiple-shaped treatment fields. It uses a device (a multileaf collimator [MLC]) that coupled to a computer algorithm, allows for “inverse” treatment planning. The radiation oncologist delineates the target on each slice of a CT scan and specifies the target’s prescribed radiation dose, acceptable limits of dose heterogeneity within the target volume, adjacent normal tissue volumes to avoid, and acceptable dose limits within the normal tissues. Based on these parameters and a digitally reconstructed radiographic image of the tumor and surrounding tissues and organs at risk, computer software optimizes the location, shape, and intensities of the beam ports to achieve the treatment plan’s goals.

Increased conformality may permit escalated tumor doses without increasing normal tissue toxicity and thus may improve local tumor control, with decreased exposure to surrounding normal tissues, potentially reducing acute and late radiation toxicities. Better dose homogeneity within the target may also improve local tumor control by avoiding underdosing within the tumor and may decrease toxicity by avoiding overdosing.

Because most tumors move as patients breathe, dosimetry with stationary targets may not accurately reflect doses delivered within target volumes and adjacent tissues in patients. Furthermore, treatment planning and delivery are more complex, time-consuming, and labor-intensive for IMRT than for 3D-CRT. Thus, clinical studies must test whether IMRT improves tumor control or reduces acute and late toxicities when compared with 3D-CRT.

Methodologic issues with IMRT studies

Multiple-dose planning studies have generated 3D-CRT and IMRT treatment plans from the same scans, then compared predicted dose distributions within the target and in adjacent organs at risk. Results of such planning studies show that IMRT improves on 3D-CRT with respect to conformality to, and dose homogeneity within, the target. Dosimetry using stationary targets generally confirms these predictions. Thus, radiation oncologists hypothesized that IMRT may improve treatment outcomes compared with those of 3D-CRT. However, these types of studies offer indirect evidence on treatment benefit from IMRT, and it is difficult to relate results of dosing studies to actual effects on health outcomes.

Comparative studies of radiation-induced side effects from IMRT versus alternative radiation delivery are probably the most important type of evidence in establishing the benefit of IMRT. Such studies would answer the question of whether the theoretical benefit of IMRT in sparing normal tissue translates into real health outcomes. Single-arm series of IMRT can give some insights into the potential for benefit, particularly if an adverse effect that is expected to occur at high rates is shown to decrease by a large amount. Studies of treatment benefit are also important to establish that IMRT is at least as good as other types of delivery, but in the absence of such comparative trials, it is likely that benefit from IMRT is at least as good as with other types of delivery.

Note: Evidence for the following abdominal and pelvic cancers has not yet been reviewed and is beyond the scope of this current policy: bladder cancer, esophageal cancer, and sarcoma.

Policy

Intensity-modulated radiation therapy may be considered medically necessary as an approach to delivering radiation therapy for patients with cancer of the anus/anal canal.

When dosimetric planning with standard 3-D conformal radiation predicts that the radiation dose to an adjacent organ would result in unacceptable normal tissue toxicity (see Policy Guidelines section), intensity-modulated radiation therapy (IMRT) may be considered medically necessary for the treatment of cancer of the abdomen and pelvis, including but not limited to:

a TD 5/5, the average dose that results in a 5% complication risk within 5 years.

b TD 50/5, the average dose that results in a 50% complication risk within 5 years.

For intensity-modulated radiation therapy (IMRT) to provide outcomes that are superior to 3-dimensional conformal radiation therapy (3D-CRT), there must be a clinically meaningful decrease in the radiation exposure to normal structures with IMRT compared to 3D-CRT. There is not a standardized definition for a clinically meaningful decrease in radiation dose. In principle, a clinically meaningful decrease would signify a significant reduction in anticipated complications of radiation exposure. In order to document a clinically meaningful reduction in dose, dosimetry planning studies should demonstrate a significant decrease in the maximum dose of radiation delivered per unit of tissue, and/or a significant decrease in the volume of normal tissue exposed to potentially toxic radiation doses. While radiation tolerance dose levels for normal tissues are well-established, the decrease in the volume of tissue exposed that is needed to provide a clinically meaningful benefit has not been standardized. Therefore, precise parameters for a clinically meaningful decrease cannot be provided.

Effective in 2015, code 77418 was deleted and new codes for simple and complex IMRT delivery were created:

The Centers for Medicare and Medicaid Services (CMS) decided not to implement this change for 2015 and instead created HCPCS G codes for the radiotherapy codes being deleted 12/31/14. So the following codes may be used for IMRT:

State or federal mandates (e.g., FEP) may dictate that all devices approved by the U.S. Food and Drug Administration (FDA) may not be considered investigational, and thus these devices may be assessed only on the basis of their medical necessity.

Rationale

This policy was originally created in 2009 and updated regularly with searches of the MEDLINE database. The most recent literature search was performed through November 17, 2014. Following is a summary of the literature to date.

Methods to plan and deliver intensity-modulated radiotherapy (IMRT) methods are not uniform.(1-3) IMRT may use beams that remain on as the multileaf collimator (MLC) moves around the patient (dynamic MLC), or that are turned off during movement and turned on when the MLC reaches prespecified positions (“step and shoot” technique). A third alternative uses a very narrow single beam that moves spirally around the patient (tomotherapy). Each of these methods uses different computer algorithms to plan treatment and yields somewhat different dose distributions in and outside the target. Patient position can alter target shape and thus affect treatment plans. IMRT may be delivered with the patient in the prone or supine position. However, data are unavailable to compare clinical outcomes for patients treated in prone versus supine positions, and consensus is lacking. Respiratory motion of the internal organs during radiation treatments is another concern when using IMRT to treat lesions in those compartments. Treatment plans are usually based on 1 imaging scan, a static 3-dimensional computed tomography (CT) image. They partially compensate for day-to-day (interfraction) variability in patient set-up, and for (intrafraction) motion of the target and organs at risk, by expanding the target volume with uniform margins around the tumor (generally 0.5-1 cm for all positional uncertainty).

Current methods seek to reduce positional uncertainty for tumors and adjacent normal tissues by various techniques. Patient immobilization cradles and skin or bony markers are used to minimize day-to-day variability in patient positioning. An active breathing control device combined with moderately deep inspiration breath-holding techniques may be used to improve conformality and dose distributions during IMRT. Other techniques being studied with internal tumors include gate beam delivery to the patient’s respiratory movement or continuous monitor of tumor (by in-room imaging) or marker (internal or surface) positions to aim radiation more accurately at the target. The impact of these IRMT techniques on outcomes for any cancer is unknown. However, it appears likely that respiratory motion alters the dose distributions actually delivered while treating patients from those predicted by plans based on static CT scans, or measured by dosimetry, using stationary (nonbreathing) targets. In addition, many tumors have irregular edges that preclude drawing tight margins on CT scan slices when radiation oncologists contour the tumor volume. It is unknown whether omitting some tumor cells or including some normal cells in the resulting target affects outcomes of IMRT. Finally, tumor size may change over the course of treatment as tumors respond or progress, which has potential effects on radiation dose delivery and distribution. Whether outcomes might be improved by repeating scans and modifying treatment plans accordingly (termed adaptive radiotherapy) is unknown.

The Advanced Technology Consortium (ATC) has helped to develop general guidelines for protocols that incorporate IMRT as an option. These guidelines were communicated to all clinical trial groups by the National Cancer Institute and clearly stated that respiratory motion could cause far more problems for IMRT than for traditional radiotherapy treatments (see ATC Guidelines For The Use Of IMRT [Including Intra-Thoracic Treatments]).

These considerations emphasize the need to compare clinical outcomes rather than treatment plan predictions to determine whether 1 radiotherapy method is superior to another.

Two reviews summarized evidence on the use of IMRT for a number of cancers, including head and neck, prostate, gynecologic, breast, lung, and gastrointestinal (GI).(4,5) The authors presented the reviews as analysis of comparative clinical studies; in reality, they categorized several small case series, using historical cohorts as controls, as comparative studies for several tumor types. This method limits the valueof the reviews in assessing the role of IMRT for the diseases addressed in this policy.

Literature searches identified no studies that directly compare health outcomes with IMRT versus those in patients treated concurrently with any other type of radiotherapy for tumors of the thorax (eg, esophagus), upper abdomen (eg, stomach, pancreas, bile duct, liver), or pelvis (eg, rectal, anal, gynecologic). Case series and single-arm studies of IMRT have been identified, including some with historical controls treated with non-IMRT methods.

Gastrointestinal Tract

Stomach

As outlined in a 2008 review article, IMRT has been investigated for treatment of gastric cancer in several studies, but, at the time, only 1 reported clinical outcomes.(1) In a small (n=7) case series, patients with stage III gastric cancer received postoperative chemoradiotherapy with 5-fluorouracil (5FU) and leucovorin and IMRT delivered to a dose of 50.4 Gy in 1.8 Gy fractions.(6) Chemoradiotherapy with IMRT was well-tolerated, with no acute GI tract toxicities (nausea, diarrhea, esophagitis) greater than grade 2.

The efficacy and safety of 2 different adjuvant chemoradiotherapy regimens using 3-dimensional conformal radiation (3D-CRT) (n=27) or IMRT (n=33) were evaluated in 2 consecutive cohorts of patients who underwent primarily D2 resection for gastric cancer.(7) The cohorts in this study were generally wellmatched, with American Joint Committee on Cancer (AJCC) advanced stage (II-IV) disease. The majority (n=26 [96%]) of those who received 3D-CRT were treated with 5FU plus folinic acid (5FU/FA); the other patient received oxaliplatin plus capecitabine (XELOX). In the 3D-CRT cohort, 13 (50%) patients completed the 5FU/FA regimen, 13 halted early because of acute toxicity or progression and received a median 60% of planned cycles. Patients in the IMRT cohort received XELOX (n=23 [70%]) or 5FU/FA (n=10 [30%]). Five of 10 (50%) patients completed all planned 5FU/FA cycles, the other 5 received only a median 60% of cycles because of acute toxicity. Thirteen (56%) treated with XELOX completed all planned cycles; the other 10 received a median of 70% planned cycles because of toxicity. Radiation was delivered to a total prescribed dose of 45 Gy/1.8 Gy/fraction in 21 (81%) of the 3D-CRT cohort patients; 5 received less than 45 Gy because of intolerance to treatment. Thirty (91%) patients in the IMRT cohort received the planned 45 Gy dosage; 2 (6%) were unable to tolerate the full course, and 1 case planned for 50.4 Gy was halted at 47 Gy. The median overall survival (OS) was 18 months in the 3D-CRT cohort, and more than 70 months in the IMRT cohort (p=0.049). The actuarial 2-year OS rates were 67% in the IMRT cohort and 37% in the 3D-CRT group (p not reported). Acute renal toxicity based on creatinine levels was generally lower in the IMRT cohort than the 3D-CRT group, with a significant difference observed at 6 weeks (p=0.021). In the 3D-CRT group, LENT-SOMA grade 2 renal toxicity was observed in 2 patients (8%) whereas no grade 2 toxicity was reported in the IMRT group. In a subsequent report from this group, which included 27 3D-CRT patients and 38 IMRT patients, median OS times for 3D-CRT were 18 months versus 43 months for IMRT (p=0.060).(8) In the 3D-CRT group, actuarial 5-year OS rates were 26% versus 47% in the IMRT group (p not reported). Median disease-free survival (DFS) in the 3D-CRT group was 14 months versus 35 months in the IMRT group (p=0.069). The actuarial 5-year DFS rate was 22% for 3D-CRT and 44% for IMRT (p not reported).

Hepatobiliary

In a retrospective series with a historical control cohort, clinical results achieved with image-guided IMRT (n=24) were compared with results with CRT (n=24) in patients with primary adenocarcinoma of the biliary tract.(9) The majority of patients underwent postsurgical chemoradiotherapy with concurrent fluoropyrimidine-based regimens. IMRT treatment plans prescribed 46 to 56 Gy to the planning targetvolume (PTV) that includes the tumor and involved lymph nodes, in daily fractions of 1.8 to 2 Gy. CRT involved 3-D planning that delivered 46 to 50 Gy in 1.8 to 2 Gy daily fractions. Both groups received boost doses of 4 to 18 Gy as needed. The median estimated OS for all patients who completed treatment was 13.9 months (range, 9.0-17.6); the IMRT cohort had median OS of 17.6 months (range, 10.3-32.3), while the CRT cohort had a median OS of 9.0 months (range, 6.6-17.3). Acute GI toxicities were mild to moderate, with no significant differences between patient cohorts. These results suggest that moderate dose escalation via CRT is technically and clinically feasible for treatment of biliary tract adenocarcinoma. However, while this series represents the largest group of patients with this disease treated with IMRT, generalization of its results is limited by the small numbers of patients, use of retrospective chart review data, nonrepresentative case spectrum (mostly advanced/metastatic disease), and comparison to a nonconcurrent control radiotherapy cohort.

Two single-arm studies reported outcomes with IMRT in patients with hepatobiliary cancers. The first study involved 42 patients with advanced (33% AJCC stage IIIC, 67% stage IV) hepatocellular carcinoma (HCC) with multiple extrahepatic metastases.(10) Among the 42 cases, 33 (79%) had intrahepatic HCC with extrahepatic metastases, and 9 (21%) had only extrahepatic lesions. The extrahepatic locations of HCCmetastatic lesions included lung (n=19), lymph node and adrenal (n=20), other soft tissues (n=6), and bone (n=5). Helical tomotherapy was performed simultaneously for all lesions in each patient, with a total radiation dose of 50 and 40 Gy to 95% of the gross tumor volume (GTV) and PTV in 10 fractions divided over 2 weeks. All received capecitabine during the course of IMRT as a radiosensitizer. After completion of tomotherapy, additional transarterial or systemic chemotherapy was administered to patients eligible for it according to tumor location. Among 31 patients who underwent hepatic IMRT, a mean of 3 courses of (range, 1-6) transarterial chemolipiodolization was performed in 23. Among 9 patients with extrahepatic lesions only, 3 received an additional 3 to 7 cycles of systemic chemotherapy consisting of epirubicin, cisplatin, and 5FU. Median follow-up was 9.4 months (range, 1.9-25.3). Tumor response was reported separately for each organ treated with IMRT. The overall tumor objective response rate was 45% for intrahepatic HCC, 68% for pulmonary lesions, 60% for lymph node and adrenal cases, and 67% for soft tissue metastases. Three cases of local tumor progression occurred within the target radiation area, including 2 intrahepatic HCC and 1 abdominal lymph node metastasis. Median OS was 12.3 months, with 15% OS at 24 months. The most common acute adverse events were mild anorexia and constitutional symptoms that occurred 1 to 2 weeks after start of IMRT, which regressed spontaneously or subsidedwith symptomatic care, and did not interfere with the scheduled delivery of IMRT. However, it is not possible to discern the impact of IMRT on adverse events because almost all occurred in patients who received chemotherapy following IMRT. However, most patients were reported to have tolerated therapy well, with no treatment-related mortality.

A second retrospective single-arm study involved 20 patients with primary, unresectable HCC who were treated with IMRT and concurrent capecitabine.(11) Patients had AJCC grade T1 (n=7) and T3 (n=13) HCC. IMRT was prescribed to a minimum tumor dose of 50 Gy in 20 fractions over 4 weeks, with the optimization goal of delivering the prescription dose to 95% of the PTV. Capecitabine was administered as radiosensitizer on the days of IMRT delivery. Eleven (55%) patients underwent at least 1 transarterial chemoembolization (range, 1-3 procedures) before radiotherapy planning. Eighteen of 20 (90%) patients completed the full course of IMRT, and 2 died before follow-up imaging was obtained. The mean survival of 18 patients who completed IMRT was 9.6 months after its conclusion. Disease progression occurred in field in 3 patients; 2 failed elsewhere in the liver. Four patients (25%) required hospitalization during therapy, due to encephalopathy (n=1), gastric ulcer (n=1), acute hepatitis (n=1), and sepsis (n=1). Four required a break from chemotherapy because of peripheral neuropathy (n=2), acute hepatitis (n=1), and sepsis (n=1). Grade 1 acute abdominal pain was observed in 15%, 30% reported grade 1 nausea, and 5% experienced grade 2 nausea. No acute or late toxicity greater than grade 2 was reported.

Pancreatic

A few case series provide clinical results with IMRT for pancreatic carcinoma. The largest series involved a retrospective analysis of 41 patients who received image-guided IMRT alone, postsurgically (41%), or with a number of concurrent primarily fluoropyrimidine-based chemotherapy regimens (88%).(12) The prescribed radiation dose to the PTV ranged from 41.4 to 60.4 Gy in daily fractions of 1.8 to 2 Gy. For all patients diagnosed with adenocarcinoma (85%), 1- and 2-year actuarial OS were 38% and 25%, respectively; median OS in resected patients was 10.8 months (range: 6.2–55.1) compared with 10.0 months (range, 3.4 to 28.0) in inoperable cases. Four patients (9.7%) were unable to complete radiotherapy as prescribed. Any upper GI acute toxicity (none grade 4) was reported in 29 (70%) patients, most commonly nausea, vomiting, and abdominal pain; any lower GI acute toxicity (<5% grade 4) was reported in 17 (42%) cases, primarily diarrhea.

A series of 20 patients with locally advanced pancreatic cancer without metastases were treated with dose-painted IMRT and chemotherapy.(13) Median OS was 11.6 months with 90% local control. Progression-free survival (PFS) was 5.9 months. Grade 2 GI toxicity was 60% and grade 3 or more GI toxicity was 20%. The authors estimated the IMRT treatment plan significantly lowered V45 values for the small bowel (p<0.001), stomach (p=0.007), and mean liver doses (p=0.001) compared with 3D-CRT. In a series of 25 patients with pancreatic and bile duct cancers (68% unresectable), 24 were treated with IMRT and concurrent 5FU; 1 refused chemotherapy.(14) Resected patients received 45 to 50.4 Gy to the PTV, whereas unresectable patients received 50.4 to 59.4 Gy. For all cancers, the median OS was 13.4 months, with 1- and 2-year OS of 55% and 22%, respectively. One- and 2-year median OS were 83% and 50%, respectively, among resected cases, and 40% and 8%, respectively, among unresected cases. IMRT was well-tolerated, with grade 2 or less acute upper GI toxicity in 80% of patients; grade 4 late liver toxicity was reported in 1 patient who survived more than 5 years.

A retrospective series included 15 patients with pancreatic adenocarcinoma (7 resected, 8 unresectable) who underwent IMRT plus concurrent capecitabine.(15) Resected cases received 45 to 54 Gy to the GTV; unresected cases received 54 to 55 Gy to the GTV; all cases received 45 Gy to the draining lymph node basin. At a median follow-up of 8.5 months, no deaths were reported among the resected patients, compared with 2 deaths in the unresected cases, yielding a 1-year OS rate of 69% among the latter. No grade 4 toxicities were reported, with the vast majority of acute toxicities reported at grade 1 (nausea, vomiting, diarrhea, neutropenia, anemia).

Gynecologic

A series of reports from a single institution provided data on clinical outcomes achieved with IMRT in women with gynecologic malignancies. Patients from an initial series16 were included in a subsequent report that comprised 40 patients who underwent IMRT to treat cancers of the cervix, endometrium, and other sites (3 patients).(17) Patients in this series underwent postsurgical IMRT (70%), with (58%) or without (42%) cisplatin chemotherapy, with a majority (60%) also undergoing postradiotherapy intracavitary brachytherapy (ICB). IMRT was prescribed to the PTV at a dose of 45 Gy, delivered in 1.8 Gy daily fractions; ICB delivered an additional 30 to 40 Gy to cervical cancer patients and 20 to 25 Gy to those with endometrial cancer. A well-matched nonconcurrent cohort of patients who underwent 4-field CRT (45 Gy to the PTV, 1.8 Gy daily fractions) using 3D planning and cisplatin chemotherapy was used to compare acute GI and genitourinary (GU) toxicities between radiotherapy modalities. No grade 3 acute GI or GU toxicities were reported in IMRT or CRT recipients. Grade 2 GI toxicity was noted in 60% of the IMRT cohort versus 91% of the CRT group (p=0.002). No significant differences were noted in the incidence of grade 2 GU toxicity in IMRT recipients (10%) compared with the CRT cohort (20%). Three other reports from the same group provide data on acute hematologic toxicity,(18) chronic GI toxicities,(19) and acute GI toxicities20 among patients who underwent IMRT with or without chemotherapy. It is unclear whether the patients in these reports are those from the initial studies or are new patients.

A small case series involved 10 patients who underwent IMRT with ICB boost for locally advanced (FIGO stage IIB and IIIB) cervical cancer.(21) During radiotherapy, all patients received cisplatin. Whole pelvic IMRT was administered to a dose of 50.4 Gy in 28 fractions, and ICB was delivered to a dose of 30 Gy in 6 fractions. The mean OS was 25 months (range, 3-27), with actuarial OS of 67%. Acute toxicities included 1 patient with grade 3 diarrhea, 1 with grade 3 thrombocytopenia, and 3 with grade 3 leukopenia. One case of subacute grade 3 thrombocytopenia was noted. These data are insufficient to draw conclusions about the efficacy or safety of IMRT in cervical cancer.

Two subsequent studies examined the use of posthysterectomy radiotherapy in women with high-risk cervical cancer. In the first study, 68 patients were treated with adjuvant pelvic radiotherapy, high doserate ICB, and concurrent chemotherapy.(22) The initial 35 cases received 4-field box CRT delivered to the whole pelvis; a subsequent 33 patients underwent IMRT. All patients received 50.4 Gy of radiation in 28 fractions and 6 Gy of high dose-rate vaginal cuff ICB in 3 insertions; cisplatin was administered concurrently to all patients. All patients completed the planned course of treatment. At median follow-up of 34.6 months (range, 12-52) in CRT recipients and 14 months (range, 6-25) in IMRT recipients, the 1-year locoregional control rate was 94% for CRT and 93% for IMRT. Grades 1 to 2 acute GI toxicities were noted in 36% and 80% of IMRT and CRT recipients, respectively (p<0.001), while acute grade 1 to 2 GU toxicities occurred in 30% and 60%, respectively (p=0.022). There was no significant difference between IMRT and CRT in the incidence of acute hematologic toxicities. Overall, the IMRT patients had lower rates of chronic GI (p=0.002) toxicities than the CRT patients.

A subsequent report from the same group included the initial 33 patients with an additional 21 cases.(23) At a median follow-up of 20 months, this study showed a 3-year DFS rate of 78% and an OS rate of 98% in IMRT recipients.

Ghandi et al reported on a prospective randomized study that compared whole-pelvic IMRT with wholepelvic CRT in 44 patients with locally advanced cervical cancer.(24) Each treatment arm had 22 patients. OS at 27 months was 87.7% with IMRT versus 76% with CRT (p=0.645). However, fewer grade ≥2 and ≥3 GI toxicities were experienced in the IMRT group than the CRT group.

In 2013, Chen et al reported on 101 patients with endometrial cancer treated with hysterectomy and adjuvant radiotherapy.(25) No significant differences between IMRT patients (n=65) and CRT patients (n=36) were found in 5-year OS, local failure-free survival, and DFS (82.9% vs 93.5% [p=0.26]; 93.7% vs 89.3% [p=0.68]; 88.0% vs 82.8% [p=0.83], respectively). However, the IMRT patients experienced less acute and late toxicities. Shih et al reported the results on 46 patients who received IMRT after hysterectomy and bilateral salpingo-oophorectomy for endometrial cancer, 78% of whom had stage III disease.(26) At a median of 52 months of follow-up, 5-year OS was 90% while toxicities were minimal.

Beriwal et al reported on 42 patients treated for locally advanced vulvar carcinoma with IMRT and chemotherapy.(27) Sixteen patients (48.5%) had complete pathologic response and 15 remained progression-free at a median of 26.5 months. Eight patients developed recurrence at the surgical site of the vulva. Chronic grade 3 or higher GI or GU toxicity did not occur.

A multicenter series included a cohort of 53 consecutive patients who received concurrent chemotherapy and IMRT.(32) Forty-eight (91%) received 5FU plus MMC; the rest received other regimens not including MMC. Radiation was delivered at 45 Gy to the PTV. Thirty-one (58%) patients completed therapy as planned, with breaks in the others because of grade 4 hematologic toxicities (40% of patients), painful moist desquamation, or severe GI toxicities. At the18-month follow-up, the local tumor control rate was 83.9% (range, 69.9%-91.6%), with an OS rate of 93.4% (range, 80.6%-97.8%). Univariate analyses did not reveal any factors significantly associated with tumor control or survival rates, whereas a multivariate analysis showed patients with stage IIIB disease experienced a significantly lower colostomy-free survival (hazard ratio, 4.18; 95% confidence interval, 1.062 to 16.417; p=0.041).

A retrospective analysis of toxicity and disease outcomes associated with IMRT was performed in 47 patients with anal cancer.(34) Thirty-one patients had squamous cell carcinoma (SCC). Patients had AJCC stage I (n=6 [13%]), stage II (n=16 [36%]), stage III (n=14 [31%]), stage IV (n=6 [13%]), or recurrent disease (n=3 [7%]). IMRT was prescribed to a dose of at least 54 Gy to areas of gross disease at 1.8 Gy per fraction. Forty patients (89%) received concurrent chemotherapy with a variety of agents including MMC, 5FU, capecitabine, oxaliplatin, etoposide, vincristine, doxorubicin, cyclophosphamide, and ifosfamide in various combinations. The 2-year actuarial OS for all patients was 85%. Eight patients (18%) required treatment breaks. Toxicities included grade 4 leukopenia (7%) and thrombocytopenia (2%); grade 3 leukopenia (18%) and anemia (4%); and grade 2 skin toxicity (93%). These rates were much lower than previous trials of chemoradiation, where grade 3 to 4 skin toxicity was noted in about 50% of patients and grade 3 to 4 GI toxicity noted in about 35%. In addition, the rate of treatment breaks was lower than in many studies; and some studies of chemoradiation include a break from radiotherapy. Some investigators believe that treatment breaks reduce the efficacy of this combined approach.

A small (n=6) case series of IMRT and concurrent infusional 5FU plus cisplatin was reported in patients with anal cancer and para-aortic nodal involvement.(35) IMRT was delivered to a median dose of 57.5 Gy to the clinical target volume, with nodal areas of involvement treated to a median dose of 55 Gy. Five of 6 patients completed the entire prescribed course of IMRT. The 3-year actuarial OS rate was 63%. Four patients developed grade 3 acute toxicities that included nausea and vomiting, diarrhea, dehydration, small bowel obstruction, neutropenia, anemia, and leukopenia. Five of 6 had grade 2 skin toxicity.

Zhu et al reported on a phase 2 trial of neoadjuvant IMRT with chemotherapy for 42 patients with stage II/III rectal adenocarcinoma.(36)Surgical resection was performed in 38 patients and pathologic complete response occurred in 6 patients. Skin, GI tract, and hematologic grade 3 toxicities were 26.2%, 14.3%, and 4.7%, respectively. No grade 4 toxicity was seen. Patients who responded well (defined as tumorregression grade [TRG] 3-4) had OS of 83.9% versus 40.7% in patients who were poor responders (defined as TRG 1-2; p=0.007).

Zhu et al also reported on a phase 2 trial of IMRT with chemotherapy for 32 patients with rectal adenocarcinoma and unresectable distant metastases.(37) IMRT was delivered to the pelvis at 45 Gy with a concomitant 10 Gy boost to the gross tumor. Surgical resection of the rectal tumor was also performed in 14 patients. Dermatitis from the IMRT around the anal verge occurred most commonly in 18.8% of patients. OS was 17.5 months and PFS was 12 months at a median follow-up of 12 months (range, 4-23). Local failure occurred in 2 patients.

Ongoing and Unpublished Clinical Trials

An online search of ClinicalTrials.gov on November 12, 2014, identified 25 phase 2 or 3 clinical trials recruiting patients to evaluate the use of IMRT in gynecologic, pancreatic, colorectal, and hepatobiliary tract cancer.

While the various physician specialty societies and academic medical centers may collaborate with and make recommendations during this process through the provision of appropriate reviewers, input received does not represent an endorsement or position statement by the physician specialty societies or academic medical centers, unless otherwise noted.

2010 Input

In response to requests, input was received from 1 physician specialty society (2 reviewers) and 3 academic medical centers while this policy was under review for May 2010. There was support for use of IMRT in a number of cancers discussed above. In general, this support was based on normal tissue constraints for radiation doses and whether these dose constraints could not be met without the use of IMRT.

2012 Input

In response to requests, input was received from 1 physician specialty society (4 reviewers) and 3 academic medical centers while this policy was under review for August 2012. The input was somewhat mixed, but there was support for use of IMRT in a number of cancers discussed above. In general, this support was based on normal tissue constraints for radiation doses and whether these dose constraints could not be met without the use of IMRT.

Summary of Evidence

The body of evidence available to assess the role of intensity-modulated radiotherapy (IMRT) in the treatment of cancers of the abdomen and pelvis generally comprises case series, both retrospective and prospective. Only 1 randomized trial has been reported that compared results of whole-pelvic IMRT with whole-pelvic conformal radiotherapy (CRT) for cervical cancer. Reports of case series, including concurrently treated control patients, are emerging. The available results are generally viewed as hypothesis-generating for the design and execution of comparative trials of IMRT versus CRT that evaluate tumor control and survival outcomes in the context of adverse events and safety.

The comparative data on use of IMRT versus 3-dimensional (3D) conformal radiation in chemoradiotherapy for anal cancer shows marked differences in rates of acute toxicity. Thus, use of IMRT in cancer of the anus/anal canal may be considered medically necessary.

For other tumors of the abdomen and pelvis, the evidence from treatment planning studies has shown that the use of IMRT decreases radiation doses delivered to normal tissue adjacent to tumor. This potentially lowers the risk of adverse events (acute and late effects of radiation toxicity), although the clinical benefit of reducing the radiation dose to normal tissue using IMRT is theoretical. Due to the limitations in this evidence, this policy underwent clinical vetting. There was support for the use of IMRT in tumors of the abdomen and pelvis when normal tissues would receive unacceptable doses of radiation. The results of the vetting, together with an indirect chain of evidence and the potential to reduce harms, led to the decision that IMRT may be considered medically necessary for the treatment of tumors of the abdomen and pelvis when dosimetric planning with standard 3D conformal radiation predicts that the radiation dose to an adjacent organ would result in unacceptable normal tissue toxicity.

Practice Guidelines and Position Statements

National Comprehensive Cancer Network Guidelines

The National Comprehensive Cancer Network (NCCN) guidelines for anal carcinoma(38) state that IMRT “may be used in place of 3D conformal RT in the treatment of anal carcinoma”; and that “Its use requires expertise and careful target design to avoid reduction in local control by so-called ‘marginal-miss’.”

NCCN guidelines for gastric cancer(39) indicate that IMRT “is appropriate in selected cases to reduce dose to normal structures such as heart, lungs, kidneys and liver.” In designing IMRT plans “for structures such as the lungs, attention should be given to the volume receiving low to moderate doses, as well as the volume receiving high doses.”

IMRT is not mentioned in the guidelines for hepatobiliary cancers.(40)

Although IMRT is mentioned as an option in NCCN guidelines for pancreatic adenocarcinoma(41) with increasing use “in the adjuvant setting with the aim of increasing radiation dose to the gross tumor/tumor bed while minimizing toxicity to surrounding tissues,” the guidelines indicate a lack of consensus on maximum radiotherapy dose in this disease.

NCCN guidelines on rectal cancer(42) indicate IMRT should only be used in clinical trials “or in unique clinical situations including reirradiation of recurrent disease after previous radiotherapy.”

In cervical cancer, NCCN guidelines43 indicate IMRT “may be helpful in minimizing the dose to the bowel and other critical structures in the post-hysterectomy setting and in treating the para-aortic nodes when necessary” such as “when high doses are required to treat gross disease in regional lymph nodes.” IMRT “should not be used as routine alternatives to brachytherapy for treatment of central disease in patients with an intact cervix.” The guidelines also mention that IMRT is “becoming more widely used” but issues with reproducibility, immobilization and definition of target “remain to be validated.”

IMRT is not mentioned in NCCN guidelines for uterine endometrial cancer.(44)

IMRT is not mentioned in NCCN guidelines for ovarian cancer.(45)

American College of Radiology

The 2014 American College of Radiology (ACR) Appropriateness Criteria panel recommends IMRT for the treatment of anal cancer is usually appropriate if performed outside of a protocol setting but is still undergoing study.(46) ACR criteria note the most appropriate radiation dose for anal cancer has not been determined and quality control and technical problems are considered challenging with IMRT such as in target volume contouring.

U.S. Preventive Services Task Force RecommendationsNot applicable.

Medicare National CoverageThere is no national coverage determination (NCD). In the absence of an NCD, coverage decisions are left to the discretion of local Medicare carriers.

Policy updated with literature search; no new references added. Policy statement changed to state that IMRT may be considered medically necessary for all anal cancers (not limited to squamous cell carcinoma). Policy statement changed to state that IMRT may be considered medically necessary for the treatment of tumors of the abdomen and pelvis when dosimetric planning predicts the volume of small intestine receiving doses >45 Gy with standard 3-D conformal radiation would result in unacceptable risk of small intestine injury. Added a policy statement that IMRT would be considered investigational for all other uses in the abdomen and pelvis. Paragraph added to policy guidelines regarding toxic radiation dose to tissues and definition of a clinically significant decrease in radiation dose.